The present invention relates generally to shoe insoles, and more particularly, to improved insoles particularly adapted for fitness and recreational walking.
According to an article in Footwear News, volume 53, number 26, page 10, research performed in 1996 by the National Sporting Goods Association indicates that Americans are using exercise walking more than any other activity as a form of physical activity. The article further notes that since 1985, the physical activity of walking for exercise increased from 41.4 million to 73.7 million exercise walkers, with the largest number of such exercise walkers ranging in age from 33 to 54 years old. Approximately seven million senior citizens, aged 55 and older, walk for fitness, making walking the number one exercise activity for senior citizens. Also of significance is the fact that treadmill use has become the second most favored activity, with approximately 36 million users in 1997.
Although there are a wide variety of shoe types that can be used to facilitate participation in fitness or recreational walking, a closer inspection of these shoes reveals that the original equipment insert is generally a flat ethylene vinyl acetate (EVA) foam material having a thickness of approximately 175 mils. However, after repeated use, even as little as eight or nine times using the footwear, the EVA foam material will compression set approximately 40 to 50%, thereby losing a significant portion of its cushioning ability. Further, the EVA foam insert generally does not provide sufficient arch support and provides little or no heel cradling effect.
In contrast, a number of insoles have been designed for vigorous sports, and thereby utilize materials which are engineered to absorb the shock of high impact activities. These sport insoles therefore mainly focus on providing shock attenuation and motion control in the heel.
In addition, walking provides very different effects than vigorous sports. Specifically, while walking imparts impacts to the heel of up to one and one-half times a person""s body weight on the shoe, running provides impacts of up to two to three times the person""s body weight on the shoe. In contrast, walking provides more dwell time in both the heel and the forefoot than running.
Therefore, it is desirable for walking to provide an insole that, while providing shock absorption and spring in the heel, also provides a substantial amount of cushion and sheer absorption to the user""s forefoot, and which is primarily directed to fitness and recreational walking.
Accordingly, it is an object of the present invention to provide an insole that overcomes the aforementioned problems.
It is another object of the present invention to provide an insole for fitness and recreational walking.
It is still another object of the present invention to provide an insole that will not compression set to a large degree over time.
It is yet another object of the present invention to provide an insole having thin and spaced apart elastic and resilient spring walls that are formed in a repeating order within a recess formed in the toe portion, and which are elastic and provide the function of a quick acting spring.
It is a further object of the present invention to provide an insole in which the spring walls are formed in a spiral pattern and reduce shear during a normal gait.
It is a still further object of the present invention to provide an insole in which the spring walls are made of a gel material.
It is a yet further object of the present invention to provide an insole having a thin shell at the underside of the mid-foot portion, and which is composed of a more rigid or stiffer material than the lower cushioning layer and provides extra support and aids the foot in normal pronation.
It is another object of the present invention to provide an insole in which the thin shell is formed from a thermoplastic composite formed primarily from filaments of fiberglass embedded in a thermoplastic material.
It is still another object of the present invention to provide an insole with an oval opening at the underside of the heel portion which includes equally spaced apart small protuberances, which provide a quicker acting spring than the remainder of the insole, but with less dampening energy absorption.
It is yet another object of the present invention to provide an insole that is easy and economical to make and use.
In accordance with an aspect of the present invention, a removable insole for insertion into footwear, includes a forefoot portion extending at least to the metatarsals of a foot; a cupped heel portion including a relatively flat central portion and a sloped side wall surrounding the relatively flat central portion; a mid-foot portion connecting together the forefoot portion and the heel portion, the mid-foot portion including a medial arch portion defined by an extension of the sloped side wall, and the forefoot portion, heel portion and mid-foot portion formed from a unitary resilient material; a recess in a lower surface of the forefoot portion, the recess having a peripheral side wall and a top wall; a shell that extends along an underside of the insole, the shell extending under the mid-foot portion, the shell being made of a resilient material that is stiffer than the unitary resilient material; and a plurality of spaced apart spring walls formed from a viscoelastic gel in the recess, the spring walls having lower edges generally coplanar with a lower surface of the forefoot portion which is in surrounding relation to the recess.
Preferably, the spaced apart spring walls are formed in a spiral shape and extend under the forefoot portion at a position where all the metatarsal heads are adapted to apply pressure thereto. In this regard, the recess occupies a greater lateral to medial area at a front thereof than at a rear thereof. The spring walls extend substantially in an anterior to posterior direction from a rear portion of the recess to a front portion of the recess, and extend substantially in a medial to lateral direction at the front portion of the recess. Preferably, the spring walls that are at a medial side of the insole extend at an inclination to the anterior to posterior direction so as to have a substantially anterior to posterior component, but also a medial to lateral component.
The shell is preferably made from a thermoplastic composite polymer formed primarily from filaments of fiberglass embedded in a thermoplastic material, and extends to a higher extent on a medial side of the mid-foot portion than at a lateral side of the mid-foot portion. Preferably, the unitary resilient material at the mid-foot portion is formed with a shallow recess at an underside thereof, and the shell is adhered in the shallow recess such that a lower surface of the shell forms a continuation of a lower surface of a remainder of the mid-foot portion surrounding the shallow recess.
In accordance with another aspect of the present invention, a removable insole for insertion into footwear, includes a forefoot portion extending at least to the metatarsals of a foot; a cupped heel portion including a relatively flat central portion and a sloped side wall surrounding the relatively flat central portion; a mid-foot portion connecting together the forefoot portion and the heel portion, the mid-foot portion including a medial arch portion defined by an extension of the sloped side wall, and the forefoot portion, heel portion and mid-foot portion formed from a unitary resilient material; a shell that extends along an underside of the insole, the shell extending under the mid-foot portion, the shell being made of a resilient material that is stiffer than the unitary resilient material; a recess at an undersurface of the cupped heel portion; and a plurality of protuberances in the recess, the protuberances forming spaced apart spring walls and the first protuberances having lower edges generally coplanar with a lower surface of the heel portion in surrounding relation to the recess.
Preferably, the first protuberances have a generally cylindrical configuration.
In accordance with still another aspect of the present invention, a removable insole for insertion into footwear, includes a forefoot portion extending at least to the metatarsals of a foot; a cupped heel portion including a relatively flat central portion and a sloped side wall surrounding the relatively flat central portion; a mid-foot portion connecting together the forefoot portion and the heel portion, the mid-foot portion including a medial arch portion defined by an extension of the sloped side wall, and the forefoot portion, heel portion and mid-foot portion formed from a unitary resilient material; a first recess at an undersurface of the cupped heel portion; a plurality of protuberances in the first recess, the protuberances forming spaced apart spring walls and the first protuberances having lower edges generally coplanar with a lower surface of the heel portion in surrounding relation to the first recess; a second recess in a lower surface of the forefoot portion; and a plurality of spaced apart spring walls formed from a viscoelastic gel in the second recess, the spring walls having lower edges generally coplanar with a lower surface of the forefoot portion which is in surrounding relation to the second recess.
In accordance with yet another aspect of the present invention, a removable insole for insertion into footwear, includes a forefoot portion extending at least to the metatarsals of a foot; a cupped heel portion including a relatively flat central portion and a sloped side wall surrounding the relatively flat central portion; a mid-foot portion connecting together the forefoot portion and the heel portion, the mid-foot portion including a medial arch portion defined by an extension of the sloped side wall, and the forefoot portion, heel portion and mid-foot portion formed from a unitary resilient material; a first recess at an undersurface of the cupped heel portion; a plurality of protuberances in the first recess, the protuberances forming spaced apart spring walls and the first protuberances having lower edges generally coplanar with a lower surface of the heel portion in surrounding relation to the first recess; a second recess in a lower surface of the forefoot portion; a plurality of spaced apart spring walls formed from a viscoelastic gel in the second recess, the spring walls having lower edges generally coplanar with a lower surface of the forefoot portion which is in surrounding relation to the second recess; and a shell that extends along an underside of the insole, the shell extending under the mid-foot portion, the shell being made of a resilient material that is stiffer than the unitary resilient material.
In accordance with a further aspect of the present invention, footwear is provided including an outer sole; an inner sole as defined above in each occurrence and connected to the outer sole; and an upper connected to at least one of the outer sole and the inner sole.
The above and other features of the invention will become readily apparent from the following detailed description thereof, which is to be read in connection with the accompanying drawings.